Metrohm 799 GPT Titrino - Manual (Page 198)

4.2. Diagnosis
799 GPT Titrino 194
4.2.3 Equipment required:
− voltage calibrator, e.g. 1.773.0010 Metrohm pH Simulator
or 1.767.0010 Calibrated Reference for mV, pH, Ω
µ
S, °C
− highly insulated interconnection cable 6.2108.060
− resistor switch-box, class 0.1 % (or resistor 14.3 k, 0.1 %)
− cable 3.496.5070
− exchange units, if possible with different cylinder volumes (or 3.496.0070 dummy exchange unit)
− stop watch or watch with second hand
− digital or analogue voltmeter (if need be, connect a calibrated recorder)
− 2 connecting cables with 4 mm banana plugs
− test plug 3.496.8550 (necessary only if plug ‘Remote’ should be checked)
− test plug 3.496.8560 (necessary only if plug ‘RS 232’ should be checked)
4.2.4 Diagnosis steps
1 Prepare instruments for diagnostic test
• Power off.
• Disconnect all external connections (cables at rear, except mains cable and key-
board).
• Remove exchange unit.
• Power on and immediately press and hold the <9> key until the powerup test pat-
tern disappears.
diagnose press key 0...9
2 Perform display test
• Press <2>.
display test
• Press .
Characters for a visual check of the display are generated on the eight lines.
Test sequence:
a) The display is cleared and overwritten from the top left to the bottom right with a dot
pattern ( ▓▓▓▓▓▓▓▓ ).
b) The display is cleared and overwritten from the top left to the bottom right with a dot
pattern( ░░░░░░░░.
c) The display is continuously cleared and overwritten from the top left to the bottom right
with the complete character set (see page 195 / Fig. 1). At the same time with moving
display the LED’s „COND.“, „STATISTICS“ and „SILO“ are swtiches on and off.
• The test sequence can be held and then continued at any time by pressing <5>.
• Block 2 is quit by pressing .
diagnose press key 0...9